Download Magnastart handbook - PDF - Iris Power Engineering

using Magnastart is dissipated in the heavy mass of the steel cores, which can absorb aconsiderable amount of energy. Advanced thermal insulation protects the coils whichremain relatively cool, and several consecutive starts may be obtained on drives with highinertial loads.Each of the coils has four connection taps brought out to studs on the front panel. By usingvarious star and delta combinations, up to 17 different starting impedances are available, toprovide the best starting characteristics on a wide range of motors.4. CONSTRUCTIONThe Magnastart chassis consists of two rectangular steel plates. Between these aresandwiched the three specially shaped, hollow steel cores, in a triangular array. The coresare specially shaped to give the special electrical characteristics required. On each core iswound a coil. On the smallest model, this is wound directly onto the core. On all othermodels the coil is supported at top and bottom by six heat-resistant supports. There is a5mm air gap between the coil and the core to thermally insulate the coil from the core,where most of the heat is dissipated.Each coil is tapped at 84% and 56%, and all the connections are brought out to the frontpanel in a rectangular array.Magnastart is built to have a large mass. The large weight of steel not only gives improvedelectrical performance, but also a high thermal capacity. Consequently, it is capable ofabsorbing the energy from a number of starts in succession.Page 6 V1.3